Improvement in metallic grinding-mills



G. PALMER.

Metallic Burrs. N0.'35,036. Patented April 22. 1862.V

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, UNITED STATES PATENT OEEICE.

GEORGE PALMER, OF LITTLESTOVN, PNNSYIIVANIA.

lMPROVEIVlENT IN METALLIC GRlNDlNG-MILLS.

Specification forming part of Letters Patent No. 35,036, dated April 22,1362.

To @ZZ whom t may concern:

Be it known that I, GEORGE PALMER, of Littlestown, in the county of Adams and State of Pennsylvania, have invented new and useful Improvementsin Metallic Grinding-Mills, and the following is a full, clear, andeXactdescription of the same, reference being had to the accompanyingdrawings, making a part of this specification, in which- Figure l showsa vertical section of the cylinder ginding surfaces. Fig. 2 shows therevolving cone with the Vmovable ventilated grinding-slats- Fig. 3represents an end view or section through the mill at the red line inFig. l.

My invention consists in attaching to a revolving cone movableventilated longitudinal slats in sections to be used in combination Withsimilar concave yielding and adjustable slats attached to the rim orcovering.

To enable others skilled in the art to make and use my invention, I willproceed to describe its construction, operation, and effects, referringto the drawings and to the letters marked thereon.

The outside covering and frame, A A, may be 4made of metal or wood andof as many pieces and such form as desired, they being secured and heldtogether by bolts and flanges or surrounded by hoops, the diameter ofthe base or large end being abou t on e-third larger than the other.

Inside of the concave covering A A are recesses c c a c, six or eight innumber, into which are fitted longitudinal. concave grinding-plates B IlB B, to be made of chilled castiron or tempered steel. 'lh ese platesare made of such width and curve as to about till the circle at thelarge ends l) b b t. At about one-third of the distance :trom the largeend .is an offset, leaving a space and recess, c, be-

tween the narrow ends ot the grindingplates B B B B.

vBetween the covering A A and the concave plates B B is left at thelarge end a space, d d d, to allow the plates to yield back and thecircle formed by the plates B B to expand when any extraneous substancecomes in contact with them that cannot be crushed. The plates I5 B areheld upto the work by springs e e e e, placed between them and thecovering A A, which are adjustable by the action of set-screws ff f, sothat any amount of pressure may be applied that is necessary to grind orpulverize various substances.

The revolving cylinder D may be made of wood or metal placed upon ashaft, G, the body being conical, so that the sides will be parallelwith the concave covering A.

In the surface of the cylinder D are a series of recesses, 7L 7L 72` 7L,made dovetailedfinto which are fitted convex grindingpla-tes E E E, madeof chilled cast-iron or tempered steel of similar construction to theconcave plates B B, having offsets and spaces between them a-t thesmallest end, where the material is fed in to be ground. The plates F Fhave a groove, t' t' 1i fz', on the underside, so that there is anairpassage the whole length between them and the body of the cylinderD,so that a tree current of air is admitted, which has a tendency to keepthe plates `from heating' by friction.

A cylinder constructed as above described has many advantages over anythat has yet come to my knowledge. The grinding-plates, being made thinand light, can be made very hard, so that they will wear much longerthan those cast in a solid form. Should they become dull and cease tooperate fast and well, or get broken, they can easily be removed andothers substituted in their places. One pattern answers to make thewhole Vseries for a cylinder, and a supply of extra plates may beobtained at any time. The same advantages are also derived by theconstruction and mode Aof inserting the stationary plates B in thecover, so that they can easily be removed and others put in theirplaces; but a very great advantage is found in having them separate andso that they can yield to allow the passage through of such substancesas are not readily crushed; and, again, they being made adjustable bysetscrews, can be regulated to act with certainty on all varieties ofgrain and other material for which mills are used.

My impro ved metallic grinding-mill may be placed in any desiredposition-either vertical, inclined, or horizontal--and works in a mostsatisfactory manner. The journals of the shaft G may run in boxes orhave a step and regulating screw or lever in the same manner as ordinarymills of like character. They may be run with much greater speed thanother metallic mills, and will consequently grind more stuit in a giventime. They may be driven by a belt and pulley or gear-Wheels and used byhorse, Water, or steam power with the most satisfactory results. Inshort, their superior is not found to exist.

Having thus fully described iny improved grinding-mill, what l claim asmy invention, and desire to secure by Letters Patent, is-

rlhe movable ventilated longitudinal grin ding-plates attached to arevolving cylinder in k sections, in the manner herein deseribed, incombination with the eene-ave grinding-plates seeured to the coveringand made yielding and adjustable by springs and set-screws or theirequivalents, in the manner as and lfor the purposes herein set forth.

GEORGE PALMER. Witnesses:

L. F. CALLAN,

W. WOODRUFF.

